Structure and Bioactivities of a Novel Polysaccharide Extracted From Dendrobium huoshanense by Subcritical Water

Optimization of Three Extraction Methods and Their Effect on the Structure and Antioxidant Activity of Polysaccharides in Dendrobium huoshanense

Dendrobium huoshanense is a famous edible and medicinal herb, and polysaccharides are the main bioactive component in it. In this study, response surface methodology (RSM) combined with a Box-Behnken design (BBD) was used to optimize the enzyme-assisted extraction (EAE), ultrasound-microwave-assisted extraction (UMAE), and hot water extraction (HWE) conditions and obtain the polysaccharides named DHP-E, DHP-UM, and DHP-H. The effects of different extraction methods on the physicochemical properties, structure characteristics, and bioactivity of polysaccharides were compared. The differential thermogravimetric curves indicated that DHP-E showed a broader temperature range during thermal degradation compared with DHP-UM and DHP-H. The SEM results showed that DHP-E displayed an irregular granular structure, but DHP-UM and DHP-H were sponge-like. The results of absolute molecular weight indicated that polysaccharides with higher molecular weight detected in DHP-H and DHP-UM did not appear in DHP-E due to enzymatic degradation. The monosaccharide composition showed that DHPs were all composed of Man, Glc, and Gal but with different proportions. Finally, the glycosidic bond types, which have a significant effect on bioactivity, were decoded with methylation analysis. The results showed that DHPs contained four glycosidic bond types, including Glcp-(1→, →4)-Manp-(1→, →4)-Glcp-(1→, and →4,6)-Manp-(1→ with different ratios. Furthermore, DHP-E exhibited better DPPH and ABTS radical scavenging activities. These findings could provide scientific foundations for selecting appropriate extraction methods to obtain desired bioactivities for applications in the pharmaceutical and functional food industries.

Lotus-Flower- and Lotus-Seedpod-Derived Polysaccharide: Structural Characterization and Biological Activity

Lotus flower polysaccharide (LFP) and lotus seedpod polysaccharide (LSP) were separated by water extract-alcohol precipitation, and their structures and biological activities were investigated. The results of monosaccharide composition showed that LFP and LSP were composed of nine monosaccharides, fucose, rhamnose, arabinose, glucose, galactose, mannose, fructose, galacturonic acid, and glucuronic acid, with the molar percentages of 0.18: 0.43: 2.26: 45.22: 32.14: 4.28: 8.20: 6.28: 1.01 and 2.70: 1.02: 8.15: 45.63: 20.63: 1.44: 2.59: 16.45. LSP and LFP exhibited molecular weights of 9.37 × 104 Da and 1.24 × 106 Da, respectively. SEM showed that LFP and LSP have similar structures; XRD analysis showed that both polysaccharides had crystalline structure and amorphous structure. The results of ABTS+, DPPH, hydroxyl radical scavenging experiment, and a reducing power experiment showed that LFP and LSP had good antioxidant capacity. Cell viability findings showed that polysaccharide concentrations of lotus flower and lotus seedpod could enhance cellular proliferation ranging from 25 to 400 μg/mL without cytotoxicity. By inducing the production of crucial proteins in the TLR4/NF-κB pathway, LFP and LSP were able to induce autophagy in RAW264.7, according to the results of the RT-PCR and Western blotting assays.

Preparation of nano-selenium from chestnut polysaccharide and characterization of its antioxidant activity

Chestnut is widely cultivated and has high nutritional value due to its richness in polysaccharides. In order to improve the antioxidant activity of chestnut polysaccharide, chestnut polysaccharide (CP) was extracted by ultrasonic-assisted water extraction and alcohol precipitation and purified by cellulose DEAE-52 exchange and Sephadex G-100 chromatography in this study. CP isolates were characterized by I₂-KI reaction, three-strand helical structure analysis, infrared spectrum analysis, and nuclear magnetic resonance detection. The results showed that CP is a pyrylan sugar with triple helical structure and connected by α-glycosidic bonds, with sugar residues 1,4-α-D-Glcp, 1,6-α-D-Galp, 1,5-α-L-Araf, 1,4-α-L-Rhap, and 1,4-β-D-Glcp in the CP backbone. After purification, the branching structure, rod, and spherical structure were significantly increased, with reduced lamellar structure. The in vitro scavenging rates of CP at 10 mg·mL^-1 against DPPH, hydroxyl radicals, and ABTS were 88.95, 41.38, and 48.16%, respectively. The DPPH free radical scavenging rate of purified polysaccharide fraction CP-1a was slightly enhanced, and the other rates showed a small decrease. Selenized chestnut polysaccharide (CP-Se) was prepared using nano-selenium method. The selenization method was optimized and stable Se-CP was obtained. When the concentration was 5 mg·mL^-1, Se-CP had significantly higher scavenging abilities 89.81 ± 2.33, 58.50 ± 1.60, and 40.66 ± 1.91% for DPPH, hydroxyl radical, and ABTS radicals, respectively, than those of CP. The results of this study provide insight into the effects purification and selenization of chestnut polysaccharide on antioxidant activity, and also provide a theoretical basis for the development of chestnut polysaccharide for use in functional foods or health products.

The Chemical Profiling and Anticancer Potential of Functional Polysaccharides from Flos Sophorae Immaturus

Polysaccharides from Flos Sophorae Immaturus (FSI) are one of its pharmacological compounds that can perform effective activities. Aiming to extract the most effective polysaccharides against hepatocellular carcinoma (HCC), the polysaccharides were separated from FSI through ultrasonic microwave extraction, and the first comparison was carried out on the characterization of the structure and its cytotoxic properties on HCC SMMC 7721 cells of undeproteinized purified polysaccharides (PFSI-1) and papain-deproteinized polysaccharides (PFSI-2) from FSI. The findings indicated that PFSI-1 and PFSI-2 had characteristic absorption peaks of polysaccharides; PFSI-1 contained three monosaccharides and PFSI-2 contained ten; and SEM, AFM, and NMR were consistent with the verification of IR polysaccharide characteristics, suggesting probable additional latent activities. The pharmacotoxic effects of both PFSI-1 and PFSI-2 on SMMC 7721 cells (p < 0.05), attenuated the migration ability of SMMC 7721 cells (p < 0.05) and promoted apoptosis (p < 0.05), with an increase in G0/G1-phase cells and decrease in S-phase cells in the PFSI-1 as well as a decrease in G0/G1-phase cells, increase in S-phase cells, and decrease in apoptosis in the PFSI-2 (p < 0.05). The significant cytotoxic effect of PFSI-2 on SMMC 7721 cells (p < 0.05) and its protective effect on human hepatic L02 cells (HL-7702) at low concentrations (p > 0.05) could indicate its potential as a new drug for the treatment of HCC.